Remarks see ticket #3313, some apply here too. - The break in the GND plane under the diff signals of the SFP receptacle is not nice and should be improved on both PCB - if we don't go to a 4-layer PCB (and remain w/ 1.55mm FR4) for a 'closer' GND plane.

let's please also add some form of polarity protection to the DC input. A regular series diode would be the simplest approach, but the TLV1117 requires up to 1.4V drop-out voltage, which makes the budget for 0.7V quite tight. (3.3+1.4=4.7V). Even a shottky diode is unrealistic at that point.

So either we use a different approach for polarity protection, or a different voltage regulator with lower drop-out voltage. Moving away from nominal 5V DC as input voltage is not really a good idea, IMHO.

There are LDOs with built-in reverse polarity protection. However, we cannot use electrolytic caps at the input (C3) in this case. But 10uF at 5V is definitely possible to get as ceramic?